Refuse incinerator



Get. 21, 1969 F. s. smPsoN REFUSE INCINERATOR 3 Sheets-Sheet l Filed Sept. l5. 1967 F. s. sxMPsoN 3,473,493

REFUSE ING INERATOR 3 Sheets-Sheet I1 .Mt I IIHNIHHM Y 1 A f W n L M M W/ W 0/ W n -W Oct. 21, 1969 Filed sept. 15, 19e? WJ///W eiliteol States Patent U5. Cl. Mil- 7 8 Claims ABSTRACT OF THE DISCLUSURE A refuse incinerator of the endless chain grate type in which the chain grate system has three sections arranged in horizontally and vertically stepped relationship with the middle section adapted to operate in the reverse direction from the other two sections, so as to move the refuse thereon in countercurrent relationship to the movement of refuse on the other two sections when it is desired to tumble the refuse; the middle section also being bodily movable to vary the degree of its underlap and overlap with respect to the other two sections, depending upon the character of the refuse being burned at the site.

The invention relates to incinerators of the type employed in municipal refuse disposal, and more particularly to agitation of the refuse being burned in the incinerator. Endless chain grate systems for moving refuse through the combustion chamber of a municipal incinerator are in extensive use and take a variety of forms. In a common form, a single endless chain grate has its upper reach (on which the refuse is disposed for burning) moving in a substantially horizontal path from the input end to the ash end of the incinerators combustion chamber; and wind boxes are provided between the upper and lower reaches of the endless chan grate for supplying air under low pressure to support combustion of the over-burden (which may be four to six feet deep) on the upper reach of the chain grate. Sometimes, the chain grate system in such an incinerator has been divided into sections, with some sections overlapping parts of other setions, so that the sections are in echelonic, or stepped, relationship with each other. In the latter cases, the refuse is charged onto one section at the input end, and moved by that section toward the ash end, but, short of the ash end, is delivered to a lower section which moves the refuse farther toward the ash end, and in turn delivers it to another lower section which continues the movement of refuse in the same direction toward the ash end, and may, depending upon the number of such sections, deliver the ash to an ashpit or bin.

As pointed out in Patent No. 3,289,617, municipally collected refuse, as delivered to incinerators, is of such varied vand heterogeneous content that no set of incinerator operating conditions can, with assurance, be depended upon to accomplish complete combustion of the refuse therein at any given increment of time. In said Patent No. 3,289,617, reference is made to refuse of the character which resists combustion whether wet or dry, and to the necessity for agitating the bed of refuse on the traveling grate in order to avoid the presence, in the residue discharged from the grate, of large volumes of unburned, but combustible, material. That patent contemplated reducing the content of unburned combustible material in the ash or residue by poking the burning bed of refuse on the chain grate by means of admitting, when necessary, a blast of air at higher pressure than the air which is introduced through the grate to support combustion and at pressures sufficient to locally lift, expand and u matted, wet, or otherwise compacted, components of the bed of refuse. While the method disclosed in said patent quite adequately performs its intended function, the high pressure blast of air does not distinguish in its elect between increments of refuse which need to be poked and those which do not. Consequently, there are occasions when loose, light, single sheets of paper may be blown out of the refuse bed, and pass out through the stack in an incompletely burned condition.

Accordingly, it is the object of the present invention to provide a method of agitating a bed of refuse as it moves through an incinerator in a manner which does not tend to lift or blow loose bits of refuse out of the bed and into the superambient atmosphere.

Another object of the invention is to provide an endless chain grate system for an incinerator of the character described, in which the degree of agitation in, and the slope of, the burning 'bed of refuse may be selectively varied depending upon the consist of the bed from time to time.

These and other objects of the invention are achieved by selectively tumbling increments of the bed of refuse when they need to be agitated, or leaving them untumbled when there is no need for agitation. The invention contemplates the provision of an endless chain grate system consisting of a series of sections in horizontally and vertically stepped relationship with one of said sections arranged in underlapping relationship to the next preceding one in the series, and in overlapping relationship with the next, if any, succeeding one in the series; and arranging said one section, selectively, to move the refuse in countercurrent relationship to its flow on the preceding and succeeding sections, if any. Preferably, said one section in said series is so constructed and arranged that the upper reach thereof on which the refuse is deposited from the preceding section) can be caused at will to move in counter-current or concurrent relationship with the flow of refuse across the series, depending upon whether or not it is desired, `at the moment, to tumble the bed of refuse. The invention further contemplates that said one of said sections of endless chain grate be arranged to be bodily movable relative to the xed preceding and succeeding sections in the series, so as to vary the degree o'f underlapping and overlapping relationship with the neighboring sections, thereby to control both the depth of the bed and its slope on the series of endless grate sections.

For illustrative embodiments of the invention, reference may be had to the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view of a municipal incinerator provided with an arrangement of chain grates constructed in accordance with the present invention;

FIGURE 2 is a sectional view taken along the staggered line 2 2 of FIGURE 1;-and

FIGURE 3 is a view corresponding to FIGURE l, but showing a modied arrangement of the chain grate which forms a part of the tumbling apparatus.

In keeping with the disclosure of my prior Patent No. 3,289,617, the chain grate system of the incinerator shown in the accompanying drawings has a receiving hopper 1 with a chute 2 extending generally downward, and provided, at its lower end, with a bale 3 for directing the input refuse generally horizontally toward the input end of a combustion chamber confined by wall 4, and having a stack 5 and an ash receptacle 6. The combustion chamber has an input port 7 through which the refuse to be incinerated passes en route from chute 2 to the interior of the chamber. In the embodiment shown, an endless chain grate 8 is arranged to have its upper reach receive the refuse descending from chute 2, and to move that refuse through port 7 to the interior of the combustion chamber, where the refuse is ignited and burns en route to ash pit 6.

The specific construction of chain grate 8, andV other chain grates to be described hereinafter, forms no part of the present invention, but reference may be had to U.S. Patents Nos. 2,862,463, 3,289,617 and 3,318,270, for the details of construction of such a chain grate.

On the combustion chamber side of port 7, chain grate is provided with a series of wind boxes 9 which are continuously supplied with air at relatively low pressure to support combustion of the refuse on that portion of the chain grate 8 which lies on the combustion chamber side of port 7, it being understood that the chain grate 8 is appropriately driven in a manner well known to those skilled in the art, so as to continuously move its over-burden from bale 3 through port 7, and toward the ash pit 6 within the combustion chamber.

As pointed out hereinbefore, the present invention contemplates that the chain grate system within the combustion chamber include at least two, and preferably three, separate chain grates arranged in stepped relationship. In the embodiment shown, the arrangement is such that chain grate 8 overhangs, or otherwise discharges its over-burden downwardly onto, an intermediate chain grate 10, which in turn is arranged to overhang a third chain grate 11, so that ash and unburned refuse reaching the end of chain grate 10 toward ash pit 6 is deposited upon the chain grate 11, and consumed by combustion thereon before chain grate 11 discharges its overburden into ashpit 6.

The intermediate chain grate 10 is provided with a series of wind boxes 12, and the chain grate 11 is provided with a series of wind boxes 13, each for the purpose of supplying air, under relatively low pressure through the chain grates, to support combustion of the bed of refuse riding on the respective chain grates.

Each of the chain grates 8, 10 and 11, in the chain grate system, is driven by any appropriate means Well known in the art, as, for example, by electric motors geared to shafts of sprocket wheels which interengage with the links of the endless chain grates respectively, all for the purpose of moving the bed of refuse within the combustion chamber from the input port 7 toward the ashpit 6. In accordance with the present invention, however, the moving bed of refuse on chain grates 8, 10 and 11 is agitated and given a reverse twist by chain grate 10. To accomplish this reverse twist or tumbling of the bed of refuse, chain grate 10 is driven in the direction opposite that in which chain grates 8 and 11 are driven. While chain grate 8 and chain grate 11 have their upper reaches driven in the direction indicated by the arrow thereon, i.e., from left to right as seen in FIGURE 1, chain grate 10 moves in the opposite direction, as shown by the arrow thereon. Thus, chain grate 10 tends to move the refuse reposing on its upper reach counter to the ow of refuse from port 7 toward ash pit 6, and in collision with the flow of refuse over the inner end of chain grate 8. In order to prevent the unburned refuse on chain grate 10 from moving through the space between the overhanging end 14 of chain grate 8 and the underlying end 15 of chain grate 10, a mold board 16 is interposed between said ends 14 and 15. The mold board 16 is contoured to plough the bulk of the refuse (e.g., all but a layer of fines, such as ash) on the upper reach of chain grate 10 in an upper direction toward end 14 of chain grate 8, and to reverse the direction of its travel. Such reversal of direction, or tumbling, removes from the surface of the upper reach of chain grate 10 such unburned and compacted material as may have been reposing thereon, without burning, due to the fact that it may have been wet, bulky, or otherwise of a nature such as to impede the ow of combustion supporting air there adjacent through the chain grate.

In spite of the tendency of chain grate 10 to constantly move its over-burden in the direction away from ash pit 6, the continual supply of additional unburned, or partially burned, refuse from chain grate 8 compels the upper increments of refuse on chain grate 10 to move constantly toward ashpit 6.

In some situations, the tumbling action just described may not be sufficient to achieve the degree of agitation of the burning bed ncessary to promote combustion Dt such refuse components as books, mail order catalogs, magazines, and the like, particularly if they are wet. To facilitate the promotion of such combustion, mold board 16 may be provided with a plurality of apertures 17 which communicate with a tuyere 18, connected to a source, such as blower 19, of air under substantially higher pressure than that which supplies the wind boxes above mentioned. The higher pressure air delivered to tuyere 18 operates in the manner disclosed in Patents Nos. 3,289,- 617 and 3,318,270, and the tuyere may, if desired, be compartmented and provided with the controls disclosed in the latter patent.

The upper increments of the bed of refuse sustained by chain grate 10, moving continuously toward ashpit 6 as above described, cascade off end 20 of chain grate 10. and are deposited upon the upper reach of chain grate 11 by `which they are moved, with continuing combustion, toward the ashpit. In order to prevent such cascading refuse from spilling through the space between end 20 of chain grate 10 and the underlying end of chain grate 11, any appropriate batle may be interposed at that point.

In the form shown in the drawing, a tray 21 extends beneath the chain grate 10 for the entire length thereofv and has an upward projection 22 adjacent end 15 tot" chain grate 10, and a downwardly sloping apron 23 adjacent end 20 of chain grate 10. The tray 21 serves the dual purpose of (l) collecting the ash and other fines which may have escaped between mold board 16 and the surface of chain grate 10, and (2,) by virtue of the downwardly projecting apron 23, preventing the spill between chain grates 10 and 11 of refuse which is cascaded from end 20 downwardly. The tray 21 also conducts the ash and other fines deposited upon upward projection 22 to, and deposits them upon, the upper reach of chain grate 11, the direction of travel of the lower reach ot' chain grate 10 facilitating such movement of the ash and other fines from 22 to 23.

Under circumstances where it is not necessary in the achievement of complete combustion of the bed of refuse to tumble it, the invention contemplates that chain grate 10 be reversed to travel in the same direction as chain grates 8 and 11. To achieve this result, all that is necessary is to provide the drive for chain grate 1t) with reversible motors, or any other conventional reversible transmission means well known in the art.

In the modified construction shown in FIGURE 3, the reference characters are the same as in FIGURE l plus 100. In the modified construction, however, the chain grate 108, adjacent input port 107, is somewhat tilted, and the intermediate chain grate 110 is mounted, with its drive and air supply, for traverse on a track between the position shown in full lines and the position shown in dotted lines, or any chosen position therebetween. Depending upon the consistence of the refuse being burned, the degree of overlap between chain grate 108 and chain grate 110 may be adjusted by traversing chain grate 110 and its adjunct parts on trackway 100. This changes the slope of the overall bed of refuse, and particularly the volume of such refuse reposing at any increment of time upon the intermediate chain grate 110. For example, if the consistence of the refuse is such that its rate of burning is inordinately slow, it is desirable that the slope of the overall bed of refuse be less, and that the depth `be less, than in cases where the bed of refuse consists of materials which are more readily combustible.

Parts of the embodiment shown in FIGURE 3 which have not been specifically described have the same structure, function, and mode of operation, as their counterparts of FIGURE 1 bearing the same reference characters minus "100."

From the foregoing description, those skilled in the art will readily understand the construction and operation of the incinerator, and realize that it accomplishes its objects. While two embodiments of the invention have been disclosed, it is not to be understood that the invention is limited to the details of such disclosure.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In the process of refuse disposal by burning it on a traveling grate system through which air is passed upwardly to support combustion, on the grate, of a deep bed of combustible refuse as said bed moves from the input end toward the ash end, the improvement which comprises, tumbling the refuse on the grate substantially midway between the input end and the ash end of said traveling grate system by moving at least a substantial part of it in counter-current relationship to the input-toash-end direction while the balance of it is being moved in concurrent relationship with said direction.

2. A refuse incinerator comprising a combustion chamber having an input end and an ash end, chain grate means for moving refuse from the input end toward the ash end while undergoing combustion, said chain grate means including an endless chain grate having an upper reach moving in counter-current relationship with said input-end-to-ash-endmovement of the refuse.

3. A refuse incinerator comprising a combustion charnber having an input end and an ash end, means for moving refuse from the input end toward the ash end while undergoing combustion, and means for tumbling the moving refuse intermediate said ends, said tumbling means being located substantially midway between said input end and said ash end, said means for moving refuse consisting of at least one endless chain grate arranged with its upper reach moving in the inlet-toashend direction, said tumbling means consisting of another endless chain grate which:

(a) is arranged in lapping relationship with, at an elevation below, and to receive refuse from the rstmentioned endless chain grate;

(b) has its upper reach moving in the ash-to-input direction; and

(c) a wind box supplying air to support combustion on its upper reach (b).

4. The refuse incinerator of claim 3 having a mold board arranged between the lapping portions of said iirst and last-mentioned endless chain grates to obstruct the movement of refuse by the last-mentioned endless chain grate toward the input end, and means for introducing high pressure air through said mold board.

5. The refuse incinerator of claim 4 having means for moving the last-mentioned endless chain grate to adjust its lapping relationship with the other endless chain grates.

6. The refuse incinerator of claim 3 having a third endless chain grate which:

(d) is aranged in lapping relationship with, at an elevation below, and to receive refuse from said tumbling means; and

(e) having its upper reach moving in the input-toash direction.

7. The refuse incinerator of claim 3 in which the direction of moveemnt of said last-mentioned endless chain grate is reversible to temporarily interrupt the tumbling.

8. A refuse incinerator having an input opening at its front and an ash receiver at its rear, a series of at least three endless chain grates in said chamber, the respective ones of said endless chain grates being mounted in downwardly and rearwardly stepped relationship so that:

(l) the front end of the first is adjacent said input opening and arranged to receive refuse therefrom,

(2) the front end of the second underlaps the rear end of the first,

(3) the front end of the third underlaps the rear end of the second,

means for driving the upper reaches of the iirst and third endless chain grates in the front-to-rear direction, and means for selectively driving the second endless chain grate so that its upper reach travels in one of:

(a) rear to front to tumble the refuse thereon; and

('b) front to rear to convey the refuse without tumbling.

References Cited UNITED STATES PATENTS 1,495,809 5/ 1924 Schneider. 2,481,504 9/ 1949 Ferro et al. 110-7 2,752,869 7/ 1956 Keenan. 2,910,021 10/1959 Neumann 110-18 3,332,375 7/1967 Ito 110-15 KENNETH W. SPRAGUE, Primary Examiner U.S. Cl. 

